The aim of the study was to identify situation assessment and decision making strategies in emergency medical services physicians and to determine whether their distribution is associated with routine and non-routine situations. The research sample included 15 physicians, who were interviewed about routine and non-routine situations from their practice. The interviews about non-routine situations were conducted using the Critical Decision Method, and its adapted version was created for the purpose of conducting the interviews about routine situations. Generally, qualitative analysis showed that intuitive strategies were most frequently used in situation assessment and decision making but they occurred more in routine situations, by contrast, deliberative strategies were used more in non-routine situations. These findings were supported by statistical tests suggesting that physicians were more likely to change strategies with respect to situational demands.